Gas masks as we know them today were created from inventions that were made over time and intended to be used by firefighters, deep sea divers, and mine workers. Morgan's invention was not similar to today's gas mask.
It was a hood that had a breathing tube attached that could be hung from the floor. This allowed a firefighter to draw air from the cleaner, lower layers of the air while fighting fires. Later, it was used for mine rescues. You can get more information about protective masks from various websites.
The tubes could be controlled to avoid gas-filled pockets or mine tunnels. The mass production of gas masks to protect soldiers against chemical attack was a result of WW1. Gas masks wouldn't have been as prominent in the history of the world without WW1 and the German Army's use of mustard gas and chlorine as weapons.
Gas mask manufacturing began in America. A Scottish chemist invented a mask using charcoal to filter out noxious gases in 1854. Two British inventors created devices that could remove solid particles and noxious gas from the air in 1871 and 1874.
They used a full hood to cover the head, and tubes connected with a canister of slightly pressured oxygen. Garrett Morgan in 1914 invented a device that was used to rescue 32 miners trapped below the surface in flooded mine caverns.
These devices were all created on the fateful day of 1915, when chemical weapons were first used on large scale. The gas mask became a much more important safety device than it was for firefighters or mine workers. The gas mask became a key element in the struggle for freedom.